[Intel-gfx] [RFC-v23 02/13] drm/i915/pxp: set KCR reg init during the boot time

[Chris Wilson]

Quoting Huang, Sean Z (2021-01-19 07:43:09)
> Set the KCR init during the boot time, which is
> required by hardware, to allow us doing further
> protection operation such as sending commands to
> GPU or TEE.
> 
> rev21:
>     - Remove "#define KCR_INIT_MASK_SHIFT (16)", but still keep the
>       macro in this .c file
>     - Write KCR_INIT reg inly for gen12 during boot, not required
>       for gen13+
> 
> Signed-off-by: Huang, Sean Z <sean.z.huang at intel.com>
> ---
>  drivers/gpu/drm/i915/pxp/intel_pxp.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> index 9bc3c7e30654..4e9cee7df4f2 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> @@ -6,6 +6,12 @@
>  #include "intel_pxp.h"
>  #include "intel_pxp_context.h"
>  
> +/* KCR register definitions */
> +#define KCR_INIT            _MMIO(0x320f0)
> +
> +/* Setting KCR Init bit is required after system boot */
> +#define KCR_INIT_ALLOW_DISPLAY_ME_WRITES (BIT(14) | (BIT(14) << 16))

What Rodrigo was saying is that this is a classic masked register, so we
should be doing:

#define KCR_INIT_ALLOW_DISPLAY_ME_WRITES REG_BIT(14)

intel_uncore_write(gt->uncore, KCR_INIT,
		   _MASKED_BIT_ENABLE(KCR_INIT_ALLOW_DISPLAY_ME_WRITES));

-Chris